1. Field of the Invention
The present invention relates generally to computing networks and, more particularly, to network address route aggregation.
2. Description of Related Art
Computing networks have developed into a resource that is employed for business, education, entertainment and recreation. Network implementations, of course, are numerous in variation and a particular configuration may depend on the specific purpose, or purposes the network is intended to serve. However, one common aspect of most computing networks is the use of network addresses. These network addresses are used to identify individual elements that are coupled with a given computer network.
One commonly known type of network addresses are Internet Protocol (IP) addresses. Such IP addresses, as just indicated, are used to identify computers, and other devices, (collectively “network devices”) that are coupled with the Internet. In this respect, IP addresses are analogous to phone numbers. Thus, an exemplary network device that is coupled with the Internet preferably has a unique IP address so that other network devices can “call” or communicate with the exemplary network device. If IP addresses were not unique, data (such as email messages or media streams) sent to a non-unique IP address would potentially be delivered to multiple networks devices, which is typically not a desirable result.
Network devices coupled with the Internet may make their IP address known to other network devices by advertising (broadcasting) a route on the Internet. Such advertisements provide information on how to contact a specific network device via the Internet using IP communication (e.g., packet switched network techniques). However, if each individual network device on the Internet were to advertise its route, those routes may flood certain parts of the Internet. Consequently, such an approach may adversely affect the performance of those networks.
One technique that has been employed to address this concern is the use of route aggregation. In this context, route aggregation may be used to advertise a single route for multiple IP addresses. In this regard, a network access server (also referred to as a remote access server or concentrator) may be used. Such a network access server (NAS) may correspond with a set (pool) of IP addresses, which are typically sequential IP addresses. As is known, IP addresses are 32 bits (binary), separated into four eight-bit fields. These IP addresses are typically presented in decimal fashion, such as, for example, 10.0.2.100. Thus, the next (sequential) IP address for an IP address pool containing this example address would be 10.0.2.101.
In current approaches, a NAS may comprise a plurality of routing devices, such as hardware routers. The NAS may also have a pool of IP addresses that it manages and assigns to users that contact the NAS (such as via a modem (wireless or phone line) or a packet network). As a result of the NAS assigning an IP address to a user, that user may access the Internet (or another appropriate network, such as a virtual private network) via a gateway included in the NAS. The NAS also advertises route information for the IP addresses it assigns to users. This route advertisement may be done in non-aggregated or aggregated fashion. However, for purposes of this remainder of this disclosure, only aggregate routes will be discussed.
Using current techniques, each of the plural routers is associated with a mutually exclusive subset of IP addresses from the total pool of IP addresses managed by the NAS. However, such an approach has certain disadvantages. For example, if one (or more) of the routing devices in the NAS assigns all of its (their) corresponding subset(s) of IP addresses, further requests made to that (those) routing device(s) will be declined. Another disadvantage of current approaches results from the fact that the number of routing devices typically determines the IP address subset size. Typically, each routing device controls (has a subset with) an equal number of IP addresses as the other routing devices to attempt to balance the “load” across the routing devices. However, this approach may lead to IP addresses being wasted (e.g. not available for use).
In this regard, if a routing device in the NAS fails, all the IP addresses associated with that routing device would be wasted, or unavailable for assignment to users. As another example, if one or more of the routing devices in a NAS are under-loaded (e.g., do not receive a proportionate number of requests for IP addresses as the other routing devices in the NAS), a disproportionate number of the IP addresses associated with the under-loaded routing device(s) may be “wasted.” Therefore, based on the foregoing, alterative methods for aggregate address routing are desirable.